Automatic slip joint



Nov. 22, 1960 F. LE BUS, SR

AUTOMATIC sup JOINT 3 Sheets-Sheet 1 Filed April 20. 1956 I INVENTOR. FL lebu: 5r

BY QW-Wt" ATTUR/VEY Nov. 22, 1960 F. L. LE BUS, SR 2,961,219

AUTOMATIC SLIP JOINT Filed April 20, 1956 5 Sheets-Sheet 2 -57 ink; i-s I i ATTORNEYQ' New 22, 1960 F. L. LE BUS, SR

AUTOMATIC SLIP JOINT 3 Sheets-Sheet 3 Filed April 20, 1956 ZJWEN TO R. Ze Bus 5/:

BY I W 7 United States Patent AUTOMATIC SLIP JOINT Franklin L. Le Bus, Sr., P.(). Box 2352, Longview, Tex. Filed Apr. 20, 1956, Ser. No. 579,491 5 Claims. (Cl. 255-28) This invention relates to rotary drilling equipment and more particularly, but not by way of limitation, to a combined slip and safety joint for a rotary drilling string utilized in the drilling or coring of oil and gas well bores, and are for any other useful operation in a well bore where it is desired to raise the top part of the drill pipe string without disturbing a lower section of the drill pipe string so that any drill bit, coring bit, fishing tool, or sand testing tool will not be moved, or its position in the well bore will not be altered by raising the upper part of the drill pipe stem. This application is an improvement over my co-pending application Serial No. 481,755, filed January 14, 1955, and entitled Slip Joints, now Patent No. 2,886,289.

In the rotary drilling of oil wells, particularly deep bores, the drill bit is secured on the lower end of a drilling string which is rotated at the surface of the well through the drilling rig which includes a rotary table and cooperating kelly therewith. The kelly is usually a' square shaped elongated member disposed in an aperture in the rotary table for movement downwardly therethrough. As the drill string proceeds downwardly, it is necessary to periodically add extra joints of drill pipe for making additional depth into the well bore. When this is necessary, the kelly is usually moved upwardly above the apertured rotary table, and the additional joint of pipe is inserted between the kelly and a previous top section of the drill pipe whereupon the drilling string is again lowered to begin the drilling operation. In the present available equipment for inserting an additional joint of pipe, it is usually necessary to raise the drill bit, or core bit from the bottom of the well an equal distance that the drill string is raised so that the extra section or joint of pipe may be added to the string.

As greater oil reserves are being sought, wells are being drilled to increasingly greater depths with resulting greater hazards and expenses. For this reason a driller desires the greatest amount of information available relating to the sub-surface formations encountered in a well bore. The usual method of obtaining the desired data is the well known procedure of coring the formation. The core barrel, which is normally used to drill through the formation, drills over a small diameter section of the formation and retains a solid unit thereof within the core barrel. This solid unit or core sample is mechanically recovered and brought to the surface of the well for careful analysis. The drilling of a well to a depth of ten thousand feet or over with a core barrel on the bottom of the drill pipe is a costly project, and for this reason it is desired to obtain maximum results with the core barrel. As a result, the use of diamond studded core bits has become generally accepted in the industry. These diamond bits are quite expensive, and every effort is made to prolong their useful life.

Most wells are drilled with a well known drilling tool called a rock bit which rotates on the bottom of the bore hole. These rock bits are provided with hardened teeth to grind up the formation, and during the drilling of hard formations, such as granite and chert, many of the drilling or coring operation of the rig. When the bit is raised olf the bottom of the well 'as heretofore mentioned, however, these floating hazards settle down into the bore hole, and when the bit is lowered to continue the drilling or coring operation, the pellets and bits of.

hard teeth are trapped under the cutting surface of the bit. When rotation of the bit is continued, the broken off hardened portions under the drill or core bit will start a rolling action that causes considerable damage 1 to the bit, particularly the expensive diamond core bit,

' so that in a very short time it becomes practically useless.

This invention is generally concerned with an improved slip joint provided with cooperating control spline members having helical tapered surfaces which greatly facilitate the telescopic operation of the slip joint when it is necessary to add additional sections of pipe to the.

drill string for a continued drilling operation. The spline members provide for the insertion of the additional sections of drill pipe without lifting of the drilling bit or core bit off the bottom of the well bore. It is also well known in rotary drilling that telescopic sections have been used in the drill strings in order to limit the weight applied to the drill bit so that drilling or coring bits would not be subject to enormous weights of the entire drill stem causing a faster dulling, or crushing of the drill bits, and if proper braking power was not applied would have a tendency to cause crooked hole drilling. This invention also provides a tool which permits substantially any predetermined weight or variation in.

weight that may be desired by the driller to enable the bit head to penetrate the formation being drilled at a the weight of the drill string acting upon the drill bit by utilization of the braking apparatus at the surface of thewell, but this practice is subject to the normal inaccuracy of the human element. With predetermined knowledge of the weight of the core barrel, the desired number of drill collars and a partial section of the slip joint the necessary weight for an efficient and regulated penetration may be readily calculated and maintained.

It is an important object of this invention to provide an improved slip joint for drilling strings which provides for the addition of extra sections of pipe in the drilling string without lifting the drilling bit from the bottom of the well bore.

And still another object of this invention is to provide a slip joint cooperating with the drilling string in such a manner that the weight of all elements of the drilling string below the slip joint and including part of the slip joint may be easily predetermined and calculated in order to make up the necessary weight required for the drill bit to penetrate the formation in a more efiicient and regulated speed of penetration into the formation being drilled.

And still another object of this invention is to provide an improved slip joint which will permit insertion of an, additional joint of drill pipe without removal of the drill bit from the bottom of the well bore and yet permit operation of the drill bit when the slip joint is in an expanded open position.

And still another object of this invention is to providev a in such a manner as to permit any variation in weight ape-ears:

as. required in any drilling. operation to penetrate formations being drilled in an eflicient manner.

And still another object of this invention is to provide an. improved slip'. joint which: controls the cir'cula tion of drilling fluid therethrough to the: bottom of the:

position and such that; noadditionalrotation of the drill stringis required .in orderto; move the siip jointfrom an extended position tov a contracted position.

And still. another. object of this invention'is to providea slip. andv safety joint for drill strings; whichis simple, practical and economical inits operation.

Other. objects: and advantages of. the invention will be" evident from; the following detailed description, read in conjunction with the; accompanying drawings, which illustratexmy invention;

In the drawings:

Figure 1 is a broken vertical elevational' viewhaving portions. in section depicting the upper portion of the novel slip joint with. certain portions in elevation and shown in dotted lines for clarity.

Figure l-A is a view similar to Fig. l ofthe lower portion of the novelslip joint for interposition in a drill. string and in a position for. left handtorquefor releas ingthe'innerwa'shpipe. V v v Figure 2 is a vertical elevational view with portions thereof in section similar to Fig. 1 showing the upper portion of the slip joint in-an extended position to pe'r-- mit the. insertion of additional pipe sections in the drill.

Sh ns:

Figure 2-A is aviewsimilar to. Fig::2 ofthe lower portion of the novel slip jointin an extended position; Figure 3. is aview similarto. Fig.1 1 showing the upper portion of the slip joint in an operating position.

Figure 3-A is a view similar to Fig. 3 of the lower portion of the slip joint inan operating position.

Figure 4 is a broken elevational view partially in section-of the upper portionof the slip joint showing the relative position of the control spline members-in one position during utilizationof the slip joint for adding drill pipe sections to the drill string. 7

Figure 5. is a sectionalvv view taken. on.line 5.-5 of Fig. 1.

Figure 6 isa sectional view taken on line 6-6 of'Fig; 3.

Referring to the drawings in detail, andv particularly- Figs. 1 and 1A, reference character 5 indicates generally a slip joint adapted to be interposed above a lower drill string- 6 disposed in awell borc 7, the bottom 280i which is indicated in Fig. l-A. A rotary Kelly member .(not shown) cooperates with a' rotary table (not shown) normally utilized for holding. a drilling string (not shown) at the surface of. the well. The rotarytable connects with the top string .of drill pipe, (notshown) which 'ex-.- tendsinto the well bore for connectionat-9- with an. upper sub member 11. The-sub member 11 is con nected through complementary threads 13 with a downwardly extending cylindricalhousing 15, in turn coopcrating with a mandrel 17 threadedly secured at 18 with an outer wash pipe 19, which is connected by complementary threads 26 to a-cylindrical packing seat tubular body 21 to providestructural housings for the slip joint 5. The sleeve 21 is threadedly-secured at 22 to a drill. pipe section 6 having a' core barrel 24 and any suitable typeof core drill 26 disposed at the lower end thereof for drilling the bottom 28' of the well bore 7. A suitable safety joint 30 is preferably interposed between the drill string 6 and the barrel 24 to permit removal of the complete core when the outer barrel is stuck, and is' the .usual practice in the industry;

An inner wash pipe'32 is threadedly secured at 33 to the upper sub member 11 and extends longitudinally substantially throughout the length of the slip joint 5. The mandrel 17 is provided with a tapered shoulder portion 34 (Fig. 1) having an upstanding reduced neck portion or sleeve 36 thereabove which is slidably interposed between the inner wash pipe 32 and the cylindrical sleeve 15. The sleeve 15 is provided with a plurality of circumferentially spaced male spline or clutch .l'ug' members 38 (shown in dotted lines in the drawings) integral with the inner periphery of the'sleeve 15, and preferably cornprises two spaced lugs 38 spaced diametrically around the circumference, but not limited thereto. It will be understood that any practical number of lugs 38 may he utilized as desired. The lugs 33 are provided with a lower helical or tapered surface 39 for a purpose as will be hereinafter set forth. The neck portion 36 is provided with a plurality of circumferentially'spaced grooves of a substantially J-shape generally indicated at 40. The grooves fact as female splines cooperating with the male lugs or splines38' for a purpose as will be hereinafter set forth.

Referring particularly to Fig. 2, each of the grooves 40 comprises a longitudinal passageway 42 extending downwardly from the top 43 of the sleeve 36 into communication with a substantially horizontally disposed passageway 44: The passageway 44 connects with a longitudinal recess or groove 46 extending upwardly from the shoulder 34 to a point spaced below the top 43 of the sleeve 36, and is provided with a shoulder 47 at the uppermost end thereof; The'groove 46 is substantially parallel to'groove 42; The substantially horizontal passageway'44 is provided with a partially helical surface or shoulder .48 provided between the grooves 42 and 46. A tapered or partially helical surface 50 (Fig. 3) is provided at the top of the female splines 40 and is in communication with the longitudinal groove 42.

The lower endof the mandrel 17 (Fig. 2) is provided with a clutch sleeve 52 having a clutch dog 54 provided The lower end portion 62 of the sleeve 15 is provided with aplurality of circumferentially spaced notches or teeth 64 for facilitating the seating of the sleeve 15 adjacent the shoulder 34 during operation of the slip joint 5. Whenthe slip joint 5 is in an extended position, as will be. hereinafter set forth, dirt particles from the well bore 7 may accumulate around the shoulder 34 and sleeve 36 which tend to hamper the telescoping of the slip joint into a contracted position. The teeth 64 facilitate the breaking up of the accumulateddirt particles upon a downward movement of the sleeve 15 and the tapered shoulder 34 directsthe loosened particles outward and downward away from the reduced neck portion 36.

A plurality of removable vertically and circumferentially spaced plug members 66 and 67 are provided in the slip joint housing structures below the mandrel 17. The plugs 66 may be removed prior to disposal of the slip joint Sfin the well'bore 7 to permit a flushing of sand, debris and settlih'gs out of the annular space 63 between the'i'nner wash pipe 32 and the outer wash pipe 19. The upper portion of the inner wash pipe 32 is provided with an enlarged'portion 70 (Fig. 2) having a plurality of circumferential packing members 72 disp sed aroundthe'outer' periphery'thereof. The sealing members 72 provide a pressure seal between the wash pipe 32 and the inner periphery of the mandrel 17 when the slip joint is in operating position.

Operation Referring to Fig. 3, the slip joint 5 is in a locked position for lowering into the Well bore 7 when the male lug members 38 are disposed adjacent the upper shoulder 47 of the groove 46. may be operated in the locked position, if desired. A right hand rotation of the upper drill string (not shown) is transmitted through the sub member 11 to the inner wash pipe 32 and the cylindrical sleeve 15. The lug 38 is disposed in the groove 46 between the key members 74 and 76 (Fig. 6) which are formed on the neck or sleeve portion 36 by the J-shaped grooves 40. Thus, a right hand rotation of the sleeve 15 moves the lug 38 into contact with the key 76, causing the mandrel 17 to rotate. In this manner the entire slip joint 5 will rotate for the drilling or coring operation. The slip joint 5 may aso be operated when the lug 38 is in a lowered position in the groove 46 as shown in Fig. 1. Right hand rotation of the sleeve 15 will move the lug 38 into contact with the key 76 for transmitting rotation to the mandrel 17.

A continuous downward feed of the kelly at the well surface (not shown) must be made as the bit penetrates the formation. The weight on the drill bit comprises the combined weights of the mandrel 17 and the structures or housings secured therebelow. Thus, the desirable weight can be predetermined for the drilling operation. From the predetermined weight calculation, the speed of penetration is regulated to the speed of the drillings, and the operator will have to lower the kelly at approximately the same rate as the core bit 26 penetrates the formation to prevent the engagement between the lug 38 and the.

shoulder 47 from reducing the weight on the bit. The clutch members are shorter than the ordinary kelly, consequently the kelly will continually feed after a normal penetration has been made so that additional sections of drill pipe may be inserted without raising the drill, or core bit, oif the bottom of the well bore. It is desirable not to raise the core bit during insertion of additional pipe sections, so that detrimental pellets, rocks and the like cannot fall under the bit before lowering it back to the bottom. Consequently, the operator must lower the kelly at approximately the same rate of speed as the core head penetrates the formation, and as soon as the kel y approaches the bottom of its feed, then it is desired to add an extra joint of pipe to continue the drilling operation. The slip joint is then operated as follows, and shown inFigs. l, 2 and 4.

When necessary to insert an additional section of drill pipe, the drilling string (not shown) is slacked off until the cooperating lug 38 moves downwardly in the groove 46 to a position substantially adjacent the tapered shoulder 34, as clearly shown in Fig. 1. The drilling string is then rotated in a left hand (i'rection and slowly raised upward within the well bore. The lug 38 will be moved into contact with the helical portion 48 of the horizontal groove 44, and into the longitudinal groove 42 to a position as shown in Fig. 4. In this position, the sleeve 15 and inner wash pipe 32 may be moved upward in a telescopic arrangement with respect to the mandrel 17, as shown in Fig. 2. This movement is a suflicient distance to permit additional drill pipe sections to be added to the drill string without moving the drill bit 26 from the bottom 28 of the well bore 7. As the wash pipe 32 moves upwardly within the slip joint 5, the clutch dogs 56 are moved upwardly therewith in order to engage the complementary clutch dogs 54, as will be hereinafter set forth. The engaged clutch dogs 54 and 56 transmit rotation to the lower portion of the drill string in an extended position of the slip joint, thereby providing for a continued drilling of the well bore' if desired. Furthermore, the. engagement Qf'llile clutch members precludes an acci-'.

It will be apparent that the slip joint 5 the dogs 54 and 56 during an extended position of the slip' bore. As the lower rim 62 of the sleeve 15 moves telescopically downward over the upper end 43 of the sleeve 36, the lugs or keys 38 will either enter the longitudinal groove 42, or the helical surface 39 of the lug 38 will come into contact with the helical surface 50 of the spline members 40. The contact between the helical surfaces 50 and 39 causes the sleeve 15 to rotate in a right hand direction and move the lug 38 into the female spline groove 42. A continued downward movement of the drill string will cause the lug 38 to travel downwardly in the spline 46 until the helical portion 39 comes into contact with the helical surface 48 of the horizontal groove 44, thus causing a further right hand rotation of the sleeve 15 to position the lug at the lower end of the groove 46 as shown in Fig. 1. The drill string may now be raised to position the lug 38 adjacent the shoulder 47 during the drilling operation as shown in Fig. 3, and may be continued as hereinbefore set forth. The slip joint 5 is so designed and constructed with the downwardly tapering helical portions to automatically position the lugs 38 within the female splines 40 without a right hand rotation of the drill string from the surface of the well, and thereby assuring a proper positioning of the telescoping joints in an efficient and expeditious manner. This automatic coupling of the slip joint precludes a hunting operation on the part of the operator that is usually necessary of the lugs within the proper groove so that the drill string can be moved vertically upward during the drilling,

operation.

In the event the drill or core bit 26 becomes stuckin the well bore, and it is necessary to back off the drill string, the drill string is lowered as hereinbefore set forth and rotated in a left hand direction to release the sleeve 15 for telescopic movement upward with respect to the mandrel 17. The drill string is then raised to move the inner wash pipe 32 upwardly through the slip joint 5 until the clutch dogs 56 are brought into engagement with the mating dogs 54. This clutch-ing engagement locks the wash pipe 32 and the mandrel 17 for either left or right hand rotation, as desired, in order to facilitate the freeing of the stuck bit. The clutch sleeve 52 provides a guide. sleeve for facilitating the engagement of the dogs 54 and. 56. The packing members 58 are disposed within the mandrel 17 when the clutch members 54 and 56 are in en-'- gagement, and thus provide a seal between the wash pipe When the slip joint 5 is in a drill-ing position, as shown in Figs. 3 and 3-A, the packing members 60 provide a seal between the packing stem 57 and the inner periphery of the sleeve 21. The upper packing members 72 (Fig. 2) disposed on the inner wash pipe 32 provide a seal between the wash pipe and the inner periphery of the mandrel 17 when the slip joint is in an operating position, as shown in Figs. 1, 1-A, 3 and 3-A. Thus drilling fluid being circulated through the wash pipe to the drill bit is precluded from any unwanted upward flow through the slipjoint 5. Furthermore, the clutching engagement of joint 5 provides for a continued drilling of the well bore,

if desired, as well as permitting a backing ofi, or the like, 1

for freeing a stuck drill bit.

:From the foregoing, it will be apparent that the present.

the wash pipe during operation of invention contemplates av slip joint assembly which per mits the insertion of an additional section of pipe in the the female grooves without additionalright hand torque applied to the. drill string. The cooperating helical surfaces automatically align the lugs with the grooves in a manner that eliminates a hunting action by the operator. The lugs are automatically moved into a'complete. disposition within the grooves without the necessity of rotating the drill string from the surface of the well bore. The helical surfaces also cooperate in the releasing of the lugs from disposition within the grooves when it is desired to telescopically extend the tool for inserting an additional section. of the drill pipe within the drill string. Thus, the helical surfaces greatly facilitate the entire telescopic operation of the slip joint.

Furthermore, the slip joint contemplates a predetermined weighton the bit which may be easily calculated to assure speed of rotation of the drill complementary to the speed of penetration of the drill bit to assure that there. is an efl'icient feeding of the kelly relative to the spline members because shoulder 47, by virtue of its contact with the upper end. of the key 38, prevents the deeper, penetration of' the drill bit and core barrel and drill collars, unless there isa feeding off of weight at the Kelly joint. In addition, the slip joint assembly is locked during lowering of the drill string into the well bore to prevent accidental telescopic spreading thereof. Changes may be made in the combination and arrangement of parts as heretofore set forth in the specification and shown in the drawings, it being understood that any modification in the precise embodiment of the invention may be made within the scope of the following claims without departing from the spirit of the invention.

I claim:

1. In a slip joint adapted to be interposed in a drill string including a bit for utilization in a well bore, said slip joint comprising an upper sleeve provided with a plurality of circumferentially spaced lugs disposed on the inner periphery thereof, a lower tubular member telescopically disposed within the upper sleeve, a plurality of substantially J-shaped grooves.circumferentially disposed on the outer periphery of the tubular member and having open upper ends for receiving the lugs, a helical surface provided at the top of the lower tubular member and in communication with the open. ends of the J-shaped grooves to direct the lugs into the grooves upon downwardtelescopic movement between the upper sleeve and lower tubular member, means provided integral with the grooves to move the lugs into full disposition within the grooves, said grooves and lugs in one position permitting an extended position for the slip joint and in another position locking the slip joint in a contracted position, means extending through the tubular member and upper sleeve for providing circulation of drilling fluid to the bit, and means cooperating between the tubular member and the upper sleeve for precluding accidental disengagement of the upper sleeve and lower tubular member a fully extended position of the slip joint.

2. In a telescopic slip joint adapted to be interposed in a drill string including a bit for utilization in a well bore, said slip joint comprising an upper sleeve member, a lower tubular member slidably disposed within the upper sleeve member, means cooperating between the tubular-member and sleeve for: providing. for alternate positions of telescopically extended and, contracted fan the slip jointwithout; raising the bit; inuthe well bore, said means comprising a plurality of male lug members circumferentially disposed on the inner periphery of the sleeve member for cooperating with a plurality of female spline membersprovided on the tubular member, each of said" female splines comprising a pair of substantially parallel longitudinal grooves having a substantially horizontal connecting passageway therebetween to provide a substantially J'-shaped groove, one of said longitudinal grooves open at the top to receive one of the lugs, thev other of said longitudinal grooves closed at the top by a v shoulder for receiving the lug thereagainst during drilling of the well bore, complementary helical surfaces provided on the lug and tubular member to automatically position the lug within the J-shaped groove upon a downward movement of the sleeve with respect to the tubular member, means extending through the tubular member and the sleeve for providing, for a circulation of drilling fluid to the bit, and means cooperating between the tubular member and the sleeve for precluding accidental disengagement of the upper sleeve from the lower tubular member in the fully extended position between the sleeve and tubular members.

3. In a telescopic slip joint adapted to be interposed in a drillstring including a bit for utilization in a well bore, said slip joint comprising an upper sleeve member provided with a plurality of circumferentially spaced male lug members disposedon the inner periphery thereof, a lower tubularmembcr slidably disposed within the upper sleeve, a plurality of substantially J -shaped female groove members provided on the tubular member for cooperating with the male lug'members to provide for telescopic movement between the sleeve and the tubular member, said J-shaped grooves provided with one open end to permit engagement and disengagement between the male lug members and the grooves, a plurality of helical shoulders provided on the tubular member to cooperate with a complementary helical shoulder provided on the lugs for automatically directing the male lugs into a fully engaged position'within the female grooves, a wash pipe extending longitudinally substantially throughout the slip joint and rigidly secured to the upper sleeve to move simultaneously therewith, a plurality of upwardly extending clutch dog members provided around the outer pe riphery of the wash pipe, a plurality of downwardly extending clutch dog members provided on the tubular sleeve and longitudinally spaced below the female grooves for engaging and interlocking with the upwardly extending dogs to transmit rotation to the bit during a telescopically extended position of the slip joint and prevent accidental withdrawal of the wash pipe from the tubular member, and passageway means providing for a circula-- tion of drilling fluid to the bit.

4. In a telescopic slip joint adapted to be interposed in a drill string including a bit for utilization in a well bore, said slip joint comprising an upper sleeve provided with a plurality of circumferentially spaced lug members disposed on the inner periphery thereof, a lower tubular member slidably disposed within the upper sleeve and provided with a plurality of substantially J-shaped groove portions circumferentially spaced on the outer periphery thereof, each ofsaid J-shaped groove portions comprising a pair of vertical grooves connected by a horizontal groove, one of said vertical grooves having the upper end thereof open, the other of said vertical grooves having the upper end thereof closed, a helical shoulder provided on the lower tubular member and in communication with the open end of the J-shaped grooves, a second helical shoulder provided at the bottom of the horizontal groove, a complementary helical shoulder provided on the lugs and adapted to contact the first mentioned helical shoulder for moving the logs into the open end of the Jshaped grooves upon a downward movement of the sleeve relative to the tubular member, said helical shoulder on the lug adapted to contact the second mentioned helical shoulder upon a further downward movement of the sleeve to move the lug into the vertical groove having a closed upper end for a full engagement of the lug and the J-shaped groove, and means cooperating between the tubular member and the sleeve for precluding a disengagement of the upper sleeve from the lower tubular member in a fully extended position therebetween.

5. In a slip joint adapted to be interposed in a drill string including a bit for utilization in a well bore, said slip joint comprising an upper sleeve provided with a plurality of circumfcrentially spaced lugs disposed on the inner periphery thereof, a lower tubular member telescopically disposed within the upper sleeve, a plurality of longitudinal grooves circumferentially disposed on the outer periphery of the tubular member, said longitudinal grooves comprising a first groove having an open upper end to receive the lugs and a second groove in communication with the first groove, said lugs provided with a helical bottom surface to cooperate with a helical surface provided at the top of the lower tubular member to direct the lugs into the open end of the first groove 10 upon a telescopic downward movement of the upper sleeve with respect to the lower tubular member, a substantially horizontally disposed helical shoulder cooperating with the first groove for contacting the lower helical portion of the lug to move the lug into a full disposition within the second groove, said grooves and lugs cooperating to provide alternate extended and contracted posi tions for the slip joint, and means cooperating between the tubular member and the upper sleeve for precluding a disengagement of the upper sleeve and lower tubular member in the fully extendedposition of the slip joint.

References Cited in the file of this patent UNITED STATES PATENTS 2,049,290 Burns et a1 July 28, 1936 2,065,262 Barklew et al Dec. 22, 1936 2,309,866 Reed Feb. 2, 1943 2,506,795 Koeln May 9, 1950 2,572,895 Waggener Oct. 31, 1951 2,585,995 Brown Feb. 19, 1952 2,851,252 Le Bus Sept. 9, 1958 2,852,231 Le Bus Sept. 16, 1958 

